A computer system such as a mobile device may include sensors. The sensors may detect attributes of the mobile device's context. The mobile device may transform the detected attributes into context data. Thus, the mobile device may have certain context awareness available in a digital format. At the same time, the mobile device may also include a messaging application. A user of the mobile device may generate a message. Portions of the message may be relevant to the context of the mobile device. Information about this context may be useful to a receiver when reviewing the message. Moreover, portions of the message and/or the context may pertain to a vendor's goods or services. A vendor may be willing to provide an incentive to a user of the mobile device (and in some cases, a receiver of the message) to include an ad message with the message.